This invention relates to an improvement in roofing tile, and more particularly to a flat shingle style roofing tile having improved ease of packaging, improved versatility in choice of installation methods, and improved roof life span.
With some previous roofing tile designs, the tile is mounted to the underlayment by mechanical fasteners such as copper or galvanized nails driven through nailholes. With other roofing tile designs, the tile is mounted to the underlayment by means of a mortar mix used as an adhesive. Still other designs require that battens, that is, long thin transverse wood strips, be installed on the underlayment, and the tiles are then hung on the battens, and optionally the tiles are secured to the battens by mechanical fasteners such as copper or galvanized nails driven through nailholes.
After a course of tiles has been installed and secured by mechanical fasteners such as copper or galvanized nails driven through nailholes, generally another course of tiles is installed higher on the roof, with a region of overlap of typically 2 to 3 inches, in which a lower portion of the upper tile course lies on top of an upper portion of the lower tile course. The overlap allows the upper tile course to protect the nails and nailholes of the lower tile course, thus minimizing leakage of water to the underlayment, and minimizing corrosion of the nails.
Because of the overlap, tiles of prior designs have sometimes given rise to a completed installation in which the upper tiles rest in part on the nails, making an uneven roof as the nails are not of uniform height and the tiles thus cannot lie correctly.
In addition to the stability provided by laying the tile onto battens, or by the use of mechanical fasteners driven through nailholes, some installations require the use of so-called "hurricane clips" . These clips are mechanical fasteners which hook over a tile at a location lower on the roof than the nailholes, typically at a lower point on the left or right edge of the tile. The use of hurricane clips may be indicated by a steep roof pitch, by prevalent high winds, or by building code requirements.
Roofing tiles are not made on site; they must be shipped from the tile factory to the building construction site. Thus it is desirable that the tiles have a shape that permits stacking and shipment on pallets or in wrapped stacks. Some tile designs do not stack neatly, not being substantially flat, and give rise to a shipping load that is unstable and difficult to handle.
With a tile roof it is desirable to minimize leakage of water past the tiles to the underlayment. In prior tile designs, such as that of U.S. Pat. No. 4,432,183, flanges are provided along the left and right edges of the tile. To one side of the tile, the "underlock" side, a groove and ridge are formed during manufacture, with the groove lying between the ridge and the balance of the tile. The groove acts as a water channel, providing a path for the flow of water down the tiles and off the roof. To the other side of the tile, the "overlock" side, an overhanging shape is provided which, when viewed from below, is seen to be a groove and ridge with shape chosen to fit neatly into the groove and ridge on the underlock side of an adjacent tile. Experience shows, however, that the groove and ridge area at the edge of the tile is traditionally the weakest part of the tile.
During installation it is preferable if the installers are able to walk on the parts of the roof, including any areas that have already been covered with tile. It is also preferable that the tile be capable of sustaining loads due to walking after the roof has been completely installed. Building code standards also impose requirements of resistance of breakage, e.g. in the event of breakage of a beam of the underlayment. In tiles of prior designs, moreover, the hurricane clip interferes with the groove and ridge of the overlock and underlock edges of the tile. If the overlock edge of a tile is in contact with the hurricane clip, then pressures due to walking on that tile may break it.
Most prior tile designs for batten installation have a batten support beam on the underside formed so as to engage the batten and to keep the tile from sliding down the roof. Such tile designs, however, generally cannot be used for non-batten nail-on installations because the batten support beam typically makes the top edge of the tile thicker than the bottom, resulting in a tile that cannot lie flat. Furthermore, such tile designs similarly cannot generally be used for mortar installations for the same reason.
The batten support beam in most prior batten-type tile designs renders the tile unusable for direct-deck installations for a second reason. The batten support beam, if in direct contact with the underlayment, gives rise to damming, resulting in water accumulation on the underlayment. Furthermore, the water passing on either side of the batten support beam may reach locations where nails have pierced the underlayment.
Most prior tile designs for nail-on mortar installations cannot generally be used for batten-type installations because the beam which would engage with the batten is missing.
It is an object of the invention to provide a flat shingle style concrete roofing tile. It is a further object of the invention to provide a tile of standard size, shaped so as to lay flat for easier packaging, and so as to permit installation using any of a number of installation means.